1. Field of the Invention
This invention is broadly concerned with a medical gas alarm system which allows monitoring of a medical gas or vacuum delivery system for low or high pressure conditions or for system shutdown due to closure of a valve in the supply line. The alarm system provides a detection switch positioned for engagement with a valve closure device and a pressure sensor each coupled to an alarm module for transmitting an alarm signal when alarm conditions are detected.
2. Description of the Prior Art
Hospitals, nursing homes, clinics and a number of other health care institutions utilize medical gasses in rendering care to patients. It is well known to administer oxygen (O.sub.2), air, nitrogen (N.sub.2) and nitrous oxide (NO.sub.2) to patients for treatment of a variety of different conditions or during surgical operations. In addition, medical gas systems also include evacuation systems which create a vacuum to be used in surgery or dentistry. A number of medical institutions now employ medical gas systems which use a central gas supply source for providing either a positive flow of treating gas or a negative flow of air to form a vacuum. These systems often utilize a network of conduits or supply lines to deliver the gas or supply the vacuum to treating locations remote from the central source. The networks often include main and branch shut-off valves to enable isolation of a portion of the network in the event of damage or fire, or to effect needed repairs.
Because the lives of patients may depend on receiving a reliable source of the treating gas, a real need has developed to ensure that the medical gas system is functioning properly, and to annunciate an alarm in the event a malfunction or alarm condition is detected. Such conditions may occur, for example, when the shut-off valve is either partially or fully closed. In that circumstance, the necessary supply of gas or the provision of vacuum may be insufficient. One example of an alarm system designed to detect valve closure is found in U.S. Pat. No. 4,879,547 to Pryslak, which shows the use of a fiber optic bundle looped though the lever of a valve and which detects closure of the valve when the fiber optic bundle is pulled out of a light detector.
There is a further need to detect other defects in the system which may impair the medical gas system effectiveness. For example, usage of the system may eventually result in low pressure conditions in the supply tank when the supply of gas is nearly exhausted. Alternatively, conditions such as a leak between the valve and the delivery outlet of the system may result in insufficient pressure or vacuum to sustain the necessary pressure level of the treating gas. There is a further need for early detection of these problems so that replacement sources of treating gas or vacuum may be provided to the patient before the medical gas delivery system becomes completely inoperative. Finally, due to the escalating costs associated with medical care and the shortage of trained nurses and technicians, monitoring of the medical gas delivery systems should be easy and capable of instant recognition of system faults at a single monitoring station remote from the supply line and valve.